Here in the UK we only sell two octane ratings. 95 and 98 RON. Leaded fuel was removed from sale on 1st January 2000. However, Leaded Four Star is now sold in a small amount of licensed stations in the UK. I always buy 95 RON, as recommended by Honda, though some drivers reckon they get better mileage with 98 RON. I tend to buy the most convenient, cheap fuel, from one of the many supermarket filling stations.

 

what ever is available in this order:

-Cheveron
-Shell
-76

91 Octane because Racecar... lol

 

 

On long trips I have gone over 550 miles on one tank! I scout the surrounding to find the cheapest gas station, usually less than $2 here in TX. It works for me.

 

This is a long, never ending thread.
I would just add...
With my 2016 Honda Fit Owners Manual the recommendation is worded as:

"unleaded gasoline, pump octane number 87 OR HIGHER".

Which would suggest to me you CAN choose to use mid-grade or premium if you wish.
It's really up to us as owners to evaluate whether we see, or feel any benefit in using the higher octane.
But 87....is simply the minimum octane...Honda isn't saying ONLY use 87 octane.

 

I just bought a 2017, here in Mexico. The manual suggests 95 octane unleaded fuel. The highest we can get here is 92. Frankly, I was surprised to see that recommendation. Thoughts?

 

Upon further research, the 95 octane is for Peruvian models, and 91 octane for the rest.

 

93 octane only

 

Thanks for quoting the manual sir! Will help those in denial that 87 is the ONLY octane our cars can use.

The other month I wanted to experiment using 87 for the next 3 fillups, I did notice a slight change in the engine's performance under heavy load especially going up steep grades. Switched back to 91 immediately and after several cycles, the air/fuel mixture stabilized and the car runs stronger again! Just coming from personal experience.

 

After many, many tanks of fuel, we settled on Top Tier brand 89 octane for our Fit. It runs like garbage on 87 (worse fuel economy and power), but doesn't seem to gain much with 93 octane.

Key to me is top tier. I wouldn't put circle K, race track, etc in my lawn equipment. They purchase from the lowest bidder. Easiest way to save on the refining and manufacturing costs of fuel is to skimp on the additives and come in on the low side of octane ratings.

 

I always use 87 octane. I have never put in anything higher. I live in a mountainous region (appalachains) and never notice any problem going up hills. No knocks no pings. I buy top tier most of the time, like maybe 75 percent of the time. If I see a non-top tier station with a very low price, like at least $0.10 US lower than top tier, or I need gas soon and there is no top tier around, I'll get non top tier. With 8 gallons of gas, 10 cents per gallon saves me 80 cents. I also look at the station. If the place looks so run down that i'm thinking "I wonder how often they change the filters on their pumps" I'll avoid that station.

The ECM for the L15B1 engine has a knock sensor. The engine has rather high compression, about 11.5 / 1. In the olden days a high compression engine would always need high octane gasoline. I'm not sure about all the technology that is involved in enabling the use of lower octane gas. If the knock sensor senses a knock and advances the ignition timing or the fuel injection timing, or whatever it does, to compensate, does that mean the engine is burning a little more fuel than it would have otherwise burned? I don't know. I could be mistaken but suspect any increased amount of low octane fuel being burned is outweighed by the extra cost of the higher octane fuel - an extra 50 cents to over a dollar per tank. As far as acceleration goes - my Fit has more than enough acceleration for passing vehicles, even if we are going up hill, and more than enough acceleration to merge onto the highway. I don't feel any need for any slight increase, and if there is any increase, I tend to think it would be negligible - perhaps measurable for for all practical purposes not noticeable. I'm not racing the car; I'm driving it around town and on highways. I'd rather save the money than get extra acceleration. At 10,000 miles per year I figure it would cost about an extra $30 per year to use high octane.

Almost always, for any brand of gas you buy, regular octane has the same additive package as high octane. The same detergent in the same amount. The only difference is the octane, which is a quality of the gasoline itself - something about the chemistry of gasoline itself, I think.

 

Stored in the ECU is the Long Term Fuel Trim and calculated constantly is the Short Term Fuel Trim.

By using 87 exclusively, your cars LTFT has settled to a low ignition map where you have constant timing retard. From there your car is looking at the current situation and adjusting the STFT as needed. The STFT is likely being adjusted slightly down (lower than your already low LTFT) when you are using cheaper fuel or are getting a bad tank.

If you are happy with your cars performance, than all is good for you.

For us, our Fit is abysmally slow and ANY improvement is very welcome. We live on the other side of the Appalachians and have our car WOT just to get up some of the hills at a reasonable pace. You must be going considerably slower than we are. With 280+ hp mini-vans with moms carting around their kids and 300+ hp workers in trucks heading to job sights, it takes our Fit everything it has to not get in their way. I literally have it in 3rd gear wide open for a short time on the way to take my son to school in the morning.

 

I have a 2015 with a CVT which can accelerate slightly faster than a 2008 with either transmission. I've never had a problem merging onto the interstate or getting up any hill. I weigh 68 kg and have about 30 kg of tools in the back. Even if I am already going 65 [edit: 65 mph] and I want to pass a tractor-trailer on the interstate, there is plenty of power left to get past them quickly. Even at a mild incline. When merging onto the interstate, I check how far back the car is, that is in the lane I am merging into (usually to the left of me). I know if I can do it without their needing to slow down, or move left, and without the distance between us ever becoming less than the safe following distance. But I think that they typically think I will not be able to make succeed at that – because I see them move over to their left – quite unnecessarily – more often than not. Yes, the little L15B1engine reaches a high rpm - but there is no sense of strain from the engine as it approaches redline. None at all. Nor does it get very much louder. Yes the CVT gets loud but the engine remains smooth and quiet. My previous car was a 2010 Toyota Matrix with a 5MT, and while it was noticeably but not dramatically slower than the Fit, it was quite adequate too. It is probably comparable to a 2008 Fit with a 5MT. I never had trouble in my air-cooled VW Beetle either - unless it had like 4 75 kg adults in it, along with 30 kg of tools. Then it would be a little slower. I'd have to leave more room between the rear my car and the front of the car to the left. But no problem in my 82 Accord with about 80 or 90 hp and weighing about 952 kg – even with full load, which was only slightly noticeable

In all of these cars, if I was in a hurry, I was able to scramble around the mass of vehicles that city traffic is comprise off. Rather than my car being in their way, their vehicles got in my way. You know, someone pulls away from the curb without looking, right in front of me, I could quickly move to the left if there was a large enough gap to do so, and maneuver myself ahead of that vehicle.

I should add that it is apparent to me that most people do not know how to merge onto a limited access highway. They will either wait and wait until there is an awful lot of room, or pull out in a manner that forces vehicles already on the highway to slow down, or move left. Even cars with large engines. They seem afraid to put the throttle pedal to the floor. I've been with drivers who are afraid of the automatic transmission kickdown. If they push the throttle pedal down far enough for it to happen, they'll pull their foot back up. Of course the Honda CVT does not try to imitate a kickdown.

 

No highways or merging where we live. We are in a mountain town with no 4 lane roads. When we are doing highway maneuvers, the Fit is OK.

Where it gets into trouble is trying to maintain 55mph on twisty two lane roads. Requires 3rd gear and WOT in uphill sections. Downhill or flat and you can pick any speed you want.

Tests I see have either car (2015 CVT or 2007 manual) at 16.8 in the quarter mile.

What would shock you would be to watch the actual throttle the car is using. Anything over about 1/3 pedal under load and the drive by wire goes to near 100% throttle (actual throttle plate opening will be ~80% since that's as high as it goes).

Next time you're going up a steep grade at 55+, go ahead and floor it. If it's like our car, you'll be surprised to find out that there's not additional acceleration available. The ECU has already sensed the load and is giving it all it's got or close to it. Honda has most people fooled into thinking the car is peppy and adequate by manipulating the throttle without you knowing.

 

"Where it gets into trouble is trying to maintain 55mph on twisty two lane roads."

On such a road, where there are small-radius curves, I usually need to slow down to 15-20 mph just to avoid tipping the car or veering off the road. Where the road goes straight for a short distance, I can sometimes get the car up to 35 mph for a short time, before I have to slow down to 15 mph again. So I would not be able to find out if the engine has enough power to get the car up to 55 mph on a such a road. But it has plenty of power to maintain 35 mph, and to accelerate rapidly from 10 mph to 20 mph. Also, where there are small-radius curves, limitations of visibility prohibit passing so I don't find out if there are limitation of acceleration.

2 ways to get to a higher elevation are a short, steep incline, or a longer shallower incline. On mountain roads, a long, shallow cannot be made straight without removing earth, so long shallow inclines are made to curve, rather than made straight. Sometimes there are also long steep inclines that are curved. But even on the shallow curved inclines, I can't safely go faster than 15-20 mph! It's the curves that limit my speed, not the engine power.

 

LOL. You would not like riding with me

I can assure you those curves can be taken at 55+mph. Our Fit bumps at the rev limiter in 3rd gear through parts of the Tail of the Dragon.

Edit - just realized the pic above is actually our Fit in the dragon. That's coming out of one of the curves that you would be "tipping the car or veering off the road." Car is on the road and not tipping. Guessing that pic was with the car at 40ish mph since it's on one of the tighter curves where Killboy hangs out.

Once again, nothing wrong at all with your style and glad you are happy with your cars performance. I would say that means it is adequate for you. Just keep in mind that it has one of the lowest power to weight ratios out there today, so there are clearly instances where some people want more.

Double Edit - have to also say that I think you are more the norm today around here. This board used to be mostly autocrossers and car junkies. Times have changed here.

 

I've been on the back of the dragon in the GK. It's got adequate power going up the mountain roads especially in sport mode using higher RPMs. Haven't had a chance to take it in the tail off the dragon, but I've ridden that in a motorbike so wouldn't be as much fun in a car anyways.

The fit does well in curvy roads with it's light weight and short wheelbase. No fear of tipping this car over

 

I routinely just run 87 octane, which is regular.
Just for kicks, this last tank I ran Premium.

This is NOT scientific, it's personal observation.
But I would say I was NOT expecting much of a difference if any at all. I've pretty much always gone by the adage, Gas is Gas.

However, it does seem like the vehicle is quieter. I don't know if I would site any great gain in operating performance, but the engine seems to idle quieter, just run quieter.

I don't want to have to pay for premium, so I'll probably switch back to regular. See if it's just been my imagination. But my first reaction is the vehicle does seem to run a little quieter on Premium.
Which is not the results I really wanted.

 

I don't have any desire for more power but I would like better cornering and better steering.

I think my 82 accord hatch was able to negotiate curves faster than the 2015 Fit, without tilting and without feeling like it would lose traction. It had better steering too. You could feel the road against the tires and if you drove straight ahead the after having turned, the road pushed the wheels back to straight-ahead. With the Fit, the power steering tends to keep the steering wheel where it is and if I want the car to return to going straight after turning left, I tend to have to turn the steering wheel back to the right, especially when the steering wheel is near the stop point. I think the accord had slightly more ground clearance, but you sat closer to the ground and the rooftop was not as high. I think it must have had a lower center of gravity. It came with Michelin tires; it had fully independent suspension on all 4 wheels. It was lighter. Weighed only about 953 kgs compared to the Fit's 1200 kgs. It felt more firmly planted. Actually felt heavier. While I owned it I lived in a flat part of the US, and only occasionally drove it on mountains, but I remember going around clover leaves to get onto of off of the highway at faster speeds than I feel comfortable doing now in the Fit. Despite the engine having more displacement, it did not have as much power - but it had more than enough for me. Some fast calculations: the Fit has a greater power to weight ratio, but the Accord had more than I needed.

The 82 Accord also had much nicer upholstery, the hatch opening was much bigger, and the cargo area was able to accomodate the width of a piece of 4 ft by 8 foot plywood, wallboard, etc. A 5-foot folding table could fit into the 82 accord hatch flat - can't fit into the fit. The accord was about the same width as the Fit and only about 6 inches longer.

 

My first Honda was a 1980 Prelude, so I can appreciate what you're saying and remember those Michelin's well. They were, by far, the best tire of the '80's.